Glossary of Terms

We know that many of the concepts used on this site can be difficult to understand. For that reason, we have provided you with a glossary to help you make sense of the terms used in Comparative Effectiveness Research. Every word that is defined in this glossary should appear highlighted throughout the Web site. When you come upon a highlighted term and would like to read the full definition, you can either click on the word to visit the glossary or roll your mouse over the word for a pop-up definition.

Definition: The practice of prescribing a drug for a condition not listed on the U.S. Food and Drug Administration (FDA) label. The label lists the medical conditions for which the FDA has approved the drug. Off-label uses may be supported by clinical evidence not available or not submitted to the FDA. Accepted medical practice often includes off-label use.

Example: For example, a group of drugs known as atypical antipsychotic agents is approved by the FDA for the treatment of schizophrenia. Clinical research studies have shown that these drugs can improve symptoms of another psychiatric disorder known as obsessive-compulsive disorder (OCD). Using an atypical antipsychotic drug to treat OCD is considered an off-label use of the drug.